I just bought a 98 blaster with a vito's 240 big bore kit, trenga racing carb, jet kit, k&n filter, and a full fmf pipe. The top end was just rebuilt like 2 hrs ago and know it sounds like it is knocking in the top end. Any ideas on what it could be?
Usually when a piston "blows up" it sends all kinds of debris down by the crank. Its possible the crank needed rebuilt but wasn't and now you have a bad crank pin/rod/main bearing.
Another possibility is the ports were champhered well enough.